Persistence of infectious bursal disease virus in New Zealand commercial egg layer flocks

Authors: Christensen NH
Publication: New Zealand Veterinary Journal, Volume 43, Issue 1, pp 43, Feb 1995
Publisher: Taylor and Francis

Animal type: Avian, Poultry, Production animal
Subject Terms: Clinical pathology, Diagnostic procedures, Notifiable organisms/exotic disease, Viral, Reproduction, Disease/defect, Infectious disease
Article class: Correspondence

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Abstract: After the discovery of infectious bursal disease (IBD) in New Zealand poultry flocks in November 1993, serological surveys of most commercial layer, broiler and breeder flocks were carried out. In January 1994, it was reported that a total of 34 infected farms had been detected. Later in the year, it became evident that on some commercial layer farms, where infection had previously been detected, subsequent flocks housed in the same building, or in adjacent buildings but tended by the same personnel, had not become seropositive to IBD. Of the 24 layer farms originally found to be seropositive, and where retesting was carried out during June and July 1994, 11 had reared seronegative flocks (R.J. Diprose pers. comm.). This was contrary to expectation, as IBD virus is generally recognised as being highly contagious, and also survives in the environment for some months. Accordingly, a trial was carried out to test whether young susceptible chickens could become infected as a result of contact with 50-week-old layers that had tested IBD-positive using an agar gel precipitation (AGP) test at 13 weeks of age (one of the original 24 positive flocks)…

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